Fine mesh screen is commonly used in door and window openings to prevent insects from gaining interior access. While effective at insect control, fine mesh screen is easily cut, making it ineffective as a security device. Building windows, especially those on a ground floor level, are commonly protected from unauthorized entry by means of window guards or grills. Often a guard formed by a framed mesh screen of heavy gauge wire or heavy gauge perforated metal is used to make it difficult for an intruder to enter.
While heavy gauge mesh or perforated metal is adequate for security purposes, it is not used to simultaneously inhibit insects, for reducing the mesh opening or perforations to a size that would inhibit insects would prohibitively restrict visibility. With both heavy gauge wire mesh screen sized to prevent insect penetration and perforated metal screen manufactured with small diameter perforations sized to prevent insect penetration there is a marked reduction in the amount of admitted light and air. Visibility is hindered by the small grid size of the screen or the small diameter perforations, particularly when looking through the guarded window at an oblique angle.
One method used to overcome the visibility limitation is to combine into one window guard two separate screens—a fine mesh screen for insect control and a perforated metal screen for security. Perforated metal screens fabricated from a single sheet of relatively thin metal perforated in a predetermined pattern to admit light and ventilating air are available. The perforated pattern is aesthetically pleasing to render the installation attractive while also providing adequate security and maintaining good visibility.
Such a combination is currently being manufactured in a permanently mounted window guard by the assignee of the present invention. However, this permanently mounted combination security perforated panel and fine mesh screen is limited in its application due to its relative high manufacturing and installation costs.
A permanently mounted window guard has a number of other disadvantages. For example, in the event of a fire or other emergency, it is not possible to leave the building through the guarded window.
Still another disadvantage to permanently mounted guards is that window guards are subjected to weathering; in time it may be necessary to replace the fine mesh screen or paint the frame. Likewise, exterior window panes require periodic cleaning. With permanently mounted window guards, these parts may be inaccessible or difficult to remove for purposes of maintenance and repair.
Accordingly, there is still a continuing need for improved combination security and insect screens; specifically, window guards that are removably mounted. The present invention fulfills this need and further provides related advantages.